Plasticizers from petroleum feedstocks and other synthetic sources have been dominant in industry since the mid-Twentieth Century following the polymerization of vinyl chloride and a need to make that polyvinyl chloride flexible. Phthalate plasticizers have been most prevalent.
Plasticizers from biological, renewable sources have been explored in recent years because of concerns about availability of petroleum feedstocks, cost, and asserted health concerns.
U.S. Pat. No. 6,797,753 (Benecke et al.) teaches the manufacture of a number of epoxidized diesters from fatty acids, including epoxidized propylene glycol disoyate. The method used by Benecke et al. begins with an esterification reaction followed by an epoxidation. This is a complicated reaction route, because of the use of strong oxidants during epoxidation and the generation of waste streams following epoxidation that require environmental attention.